Firearm trigger mechanisms typically include numerous interconnected components that require precise manufacturing and calibration to ensure proper engagement for consistent firing of the firearm. Each trigger component includes precisely machined surfaces that interlock and disengage with adjoining surfaces to provide consistent, crisp trigger engagement and release. For example, pulling a firearm trigger causes the multiple interlocking surfaces of the trigger mechanisms to slide with respect to each other to release a striking element (e.g., a firing pin, hammer, bolt, striker, etc.) from an initial or primed position. Upon release, a spring pushes the striking element forward to ignite the primer of a cartridge, causing a bullet to be expelled from a barrel of the firearm. When the striking element is in the initial primed position, a retention component (often referred to as a sear) holds the striking element in a fixed position and prevents the spring from pushing the striking element towards the cartridge. The sear is positioned in the travel path of the striking element (e.g., in the direction of the spring force) to prevent forward movement of the striking element. Pulling the trigger moves the sear out of the way of the striking element, thereby allowing the spring to push the striking element towards the cartridge and causing the firearm to fire.
Before firing, the force exerted by the spring causes the striking element to apply pressure on an engagement surface of the sear. In typical firearm firing mechanisms, the position of the sear during the process of pulling the trigger (i.e., the process of moving the sear out of the way of the striking element), is directly dependent on the position of the trigger as the trigger is pulled from the initial position to the second position. When the trigger has been pulled only partway between the initial position and the second position, the sear is only partially moved out of the way of the striking element. At this point, the force exerted by the spring on the striking element remains unchanged, while the surface area of the sear's engagement surface has decreased, thereby increasing the stress on the sear's engagement surface.
To ensure that the engagement surface of the sear does not deform due to the increased stress, the sear is formed from specific materials that undergo intricate material processing (e.g., extensive heat treatment processes) in order to increase the hardness of the sear's engagement surface. Despite the laborious manufacturing, however, repeated and prolonged use of the firearm can still result in deformation of the sear.